GCP - Load balancing with https and urlmap (backend bucket)

gcp-load-balancing.md

1. Step: Create a Backend Bucket

• Purpose: The backend bucket is where your static files (e.g., images, CSS, etc.) are stored.
• Command:

  gcloud compute backend-buckets create origin-cdn-store \
      --gcs-bucket-name=your-gcs-bucket-name

• What it does: This creates a backend bucket named origin-cdn-store, which is linked to a Google Cloud Storage (GCS) bucket where your content is hosted.

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2. Step: Create the URL Map

• Purpose: The URL map defines how traffic should be routed based on URL patterns or hostnames.
• Command:

  gcloud compute url-maps create store-url-map-prd \
      --default-backend-bucket=origin-cdn-store

• What it does: This creates a URL map called store-url-map-prd. Any traffic not explicitly matched by a specific rule will be routed to the origin-cdn-store backend bucket by default.

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3. Step: Add Host and Path Rules to the URL Map

• Purpose: To route traffic based on specific hostnames (like cdn.store.com.br) and paths (like /images/*).
• Command:

  gcloud compute url-maps add-path-matcher store-url-map-prd \
      --default-backend-bucket=origin-cdn-store \
      --path-matcher-name=cdn-rules \
      --new-hosts=cdn.store.com.br \
      --path-rules="/=origin-cdn-store,/images/*=origin-cdn-store"

• What it does:
  • Adds a path matcher named cdn-rules to the URL map.
  • Routes all traffic from the domain cdn.store.com.br to the backend bucket origin-cdn-store.
  • Specifies that both the root path (/) and any paths under /images/ should also be routed to origin-cdn-store.

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4. Step: Verify the URL Map

• Purpose: To ensure that your URL map was created correctly and routes are set up.
• Command:

  gcloud compute url-maps describe store-url-map-prd

• What it does: This shows the configuration of your URL map, including the host rules and path matchers you've set up.

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5. Step: Create the HTTPS Proxy

• Purpose: The proxy handles HTTPS traffic and links the URL map with your SSL certificate.
• Command:

  gcloud compute target-https-proxies create store-https-proxy-prd \
      --url-map=store-url-map-prd \
      --ssl-certificates=store-prd-cert

• What it does: This creates an HTTPS proxy (store-https-proxy-prd) that secures the connection using store-prd-cert and routes traffic according to the rules in the URL map (store-url-map-prd).

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6. Step: Create a Forwarding Rule

• Purpose: The forwarding rule tells Google Cloud where to send incoming traffic (to your proxy) and which IP address it should listen on.
• Command:

  gcloud compute forwarding-rules create store-https-lb-forwarding-rule-prd \
      --address=store-prd-lb-cdn-ip \
      --global \
      --target-https-proxy=store-https-proxy-prd \
      --ports=443

• What it does: This creates a forwarding rule that listens for HTTPS traffic on port 443 and routes it to your HTTPS proxy. The static IP store-prd-lb-cdn-ip is assigned to this rule, so traffic to your domain (cdn.store.com.br) is sent to the load balancer.

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Summary of the Flow:

1. Backend Bucket: Stores your content (origin-cdn-store).
2. URL Map: Routes traffic to the backend bucket, using rules to match specific hostnames and paths.
3. HTTPS Proxy: Ensures traffic is securely routed and handles SSL certificates.
4. Forwarding Rule: Directs traffic to your proxy and assigns a static IP.